Due to its advantages of wide fuel adaptability, high combustion efficiency, low nitrogen oxide emission, efficient desulfuration, excellent load regulation performance and the like, the circulating fluidized-bed boiler combustion technology is universally recognized as the most promising clean, energy-saving and environmentally-friendly combustion technology. The energy-saving and environmentally-friendly industry ranks in the first among seven strategic emerging industries in China, and the fluidized-bed boiler is listed first in the “twelfth-five” energy-saving and environmentally-friendly industry development planning of China. From the perspective of China's manufacturing industry, this product belongs to the traditional industry; while from the perspective of energy conversation and environmental friendliness, this product belongs to a novel strategic industry.
As one important thermal power equipment in the national economy, boilers are widely applied in electric power, machinery, metallurgy, chemical industry, spinning, papermaking, food, industrial and civil heating and other industries, and are known as one industry eternally coexistent with human beings.
Circulating fluidized-bed boilers not only have the unique advantages of high combustion efficiency, high desulfuration and denitrification efficiency, low cost, wide coal adaptability, combustibility for low calorific value coal and low-grade coal and the like, but also have unique advantages in biomass power generation and municipal garbage power generation. Apparently, the circulating fluidized-bed boilers have the advantages of not only the conventional fire coal, but also the new energy resource industry. If there is a large breakthrough on this technology to adapt to the wide popularization in the market, the circulating fluidized-bed boilers will certainly have a significant influence on the energy conversation, consumption reduction and emission reduction in China or even in the whole world.
As a core component of a circulating fluidized-bed boiler, a circulating fluidized-bed gas-solid separator is known the heart of the boiler and mainly functions as separating a large amount of high-temperature solid particles from airflow, and then feeding the solid particles back to the hearth to maintain a fast fluidization state within the combustion chamber and ensure multiple times of circulation, repeated combustion and reaction of fuel and a desulfurizer, so as to achieve ideal combustion efficiency and desulfurization/denitrification efficiency. Accordingly, for a circulating fluidized-bed boiler, the performance of the gas-solid separator directly influences the running of this boiler. Generally, the form, operating effect and service life of a separator are regarded as marks of a circulating fluidized-bed boiler, In a sense, the performance of a circulating fluidized-bed boiler depends on the performance of the separator, and the development of the circulating fluidized-bed technology also depends on the development of the separation technology. At present, the most prevailing circulating fluidized-bed separators having the highest share in the Chinese market are high-temperature cyclone separators made of refractory material. However, such high-temperature cyclone separators mainly have the disadvantages of high resource consumption, many performance shortcomings, high wind velocity and large resistance at the tangential inlet, and high power consumption of the draft fan; and have the following serious shortcomings: due to the high-velocity reverse flowing of gas and solid from the output of the hearth to the storage bin, a large amount of ash is carried in the airflow; the initial emission concentration of fume is very high, so the wear-resistant process to the fume inlet on the convection heating face is made completed and the convection heating face is likely to be worn and to have dust deposited thereon; the service life of the boiler is shortened, the thermal resistance is increased, the heat transfer coefficient is decreased, and the deashing strength is weakened. In some cases, to solve these shortcomings, intermediate- and low-temperature separation modes are employed. Although these two separation modes can improve the wear, they have the following largest disadvantage that fine particles and ash carried by airflow from the outlet of the hearth can not continue to combust so that the content of carbon in ash is high. In some cases, to solve this disadvantage to reduce the flow velocity and improve the fuel fineness and to improve the main efficiency parameters by the incremental cost of energy consumption, a high-temperature cyclone separation mode is employed. Although this separation mode has the advantage of reducing the content of carbon in ash, the high original emission concentration of fume is still not solved, and the use of wear-resistant measures at the inlet end of the convection heating face is complicated and still has hazards.
As a dry cyclone separator utilizes a large amount of wear-resistant and thermal insulating material, both the raw material cost and the manufacturing and installation cost of the separator are increased, large thermal inertia and thermal loss are also caused, Such a separator is likely to suffer coke formation at a high temperature, and the boiler is slow to start and stop.
For various inertia separators ever popular in China, by changing the flow direction of fume to collide with an object, separation elements in various intensive structure forms are provided in a fume passage, For example, S-shaped planar flow separators, shutter type separators and groove type separators are all inertia separators. Such a gas-solid separation mode not only artificially increases the flowing resistance and the power consumption, but also reduces the separation efficiency and makes a large amount of ash in the airflow, and the separation elements are likely to be deformed and damaged. Therefore, circulating fluidized-bed boilers using various inertia separators ever popular in China have been gradually driven out of the market.
For circular and square steam/water-cooling cyclone separators currently popular in Europe and America, the amount of wear-resistant material is reduced to solve the shortcomings of large thermal inertia and thermal loss so that the boilers are less likely to be coked and quick to start and stop. but there are still shortcomings of high power consumption of the draft fan and high original emission concentration both resulted from high wind velocity large resistance, serious elutriation and entrainment of ash. As the circular steam-cooling cyclone separators have high steel consumption, complicated manufacturing process and thus high price, it is difficult for customers to use such circular steam-cooling cyclone separators, thereby resulting in very low market share. Although square steam-cooling cyclone separators have low steel consumption and superior manufacturing process, the separation efficiency and stability of the square steam-cooling cyclone separators are lower than those of the circular steam-cooling cyclone separators.
In the present invention, by applying, a theory of inertia separation of dust due to sudden large-angle change of flowing direction and collision with tube bundles, a theory of velocity reduction and gravity settlement due to sudden capacity expansion, a theory that the fume may settle naturally when the flow velocity of the fume is 3 m to 5 m, and a theory that both a better heat transfer coefficient and a better economic velocity may be realized when the flow velocity of the fume is ≤5.10 m, all to inertia-gravity separators, thereby bringing the multifunctional performance of a water-cooling inertia-gravity separator into full play. Particularly, the organic combination of inertia separation and gravity separation effectively strengthens the gravity settlement effect and may realize the effective separation of fine particles having a specific gravity higher than that of air from a large amount of ash.
The gas-solid separator in the circulating fluidized-bed boiler as disclosed in Patent No. ZL201110036996.8 and Application No. 201110383051,3 has many advantages in comparison to a high-temperature cyclone separator, for example, low flowing resistance, saving of power consumption of the draft fan, saving of wear-resistant high-temperature material due to the structure of the water-cooling separator. However, due to the misunderstanding of the original conception and the theoretical method, the structure has serious shortcomings. For example, the wear-resistant communicating tube and the equalizing and separating tube bundles at the inlet and outlet of a turning passage occupy the cross-section of the upward and downward flues and increase the volume, and the complicated process influences the operating stability of the separator. As the rear wall of the hearth and the front wall of the shaft absolutely may be used as the common wall of the front and rear ways of the separator, the tube bundle in the vertical segment of the front and rear was of the separator is unnecessary and has negative effects. If the fume velocity of the upward flue of the separator is 3 M, the volume will certainly be increased greatly, so that it is inappropriate for development towards large scale. A secondary low-temperature downward-exhaust cyclone separator has the following shortcomings that: first, the flowing resistance is high; second, the separation efficiency is low; and third, it is unable to realize automatic discharge of deposited ash from the rear of the ventilator.
As the front and rear walls of the separator provided by the present invention share the same walls with the rear wall of the hearth and the front wall of the shaft, all the shortcomings are eliminated. The fume velocity of the downward flue of the primary high-temperature water-cooling inertia gravity separator may be 5 M to 50 M, and the fume velocity of the outlet of the downward flue may be 10 M to 15 M or 20 M, which not only is advantageous for the enhancement of heat transfer and the prevention of the volume increase of the boiler, but also may effectively increase the multiple of sudden capacity expansion and velocity reduction and reduce the fume velocity at the inlet end of the upward flue. The fume velocity at the inlet end of the upward flue is ≤3 M or 5 M. A single-stage or multi-stage high-temperature over-heater is disposed at a distance away from the inlet end of the upward flue, and the fume velocity is ≤10 M, so that the heat transfer may be enhanced and both the flowing resistance and the power consumption of the draft fan may be reduced due to the economic flow velocity. A space from the lower end of the high-temperature over-heater to the upper end of the storage bin is not only a large capacity-capacity-expanding space solid settlement chamber but also a burn-out chamber where combustibles are allowed to be fully burned, so that the primary high-temperature water-cooling inertia-gravity separator may naturally realize multiple functions of efficient gas-solid separation, sufficient combustion and efficient radiative-convective heat transfer. The sudden capacity expansion and velocity reduction at the output of the downward flue is advantageous for gas-solid separation and radiative heat transfer, and the low flow velocity at the inlet end of the upward flue is advantageous for the gravity settlement of fine particles and ash into the storage bin so as to reduce airflow entrainment. The high-temperature over-heater disposed at a vertical segment of the upward flue is advantageous for efficient convective heat transfer, and the high-temperature over-heater disposed on the upward flue, as a convection heating face and also a gas-solid separation element, is advantageous for the collision of fine particles and ash thereto to realize efficient convective heat transfer and inertia separation. Particularly, as the back-feeding valve is directly communicated to the hearth, the height occupied by the back-feeding leg is omitted, so that an effective space is vacated, it is advantages for the reduction of the height of the boiler body or the multifunctional performance of the primary high-temperature water-cooling inertia-gravity separator; and the material is quicker and smoother to be back-fed to the hearth. The principle of the secondary low-temperature inertia-gravity water-cooling separator is the same as the primary separation. The ash is forced to directly fall to the bottom of the storage bin by the guiding fume directly-raising storage bin spacer, so that an ultra-high gas-solid separation efficiency, an ultra-low original emission concentration of fume and a small size of the boiler are ensured. 27 solutions provided by the present invention are suitable for enterprises having different boiler model, different coal type, different water quality, different customer tolerance and different construction equipment, and may be combined and integrated with each other for secondary innovation.
An object of the present invention is to eliminate all shortcomings of the present circulating fluidized-bed boilers and provide a circulating fluidized-bed boiler integrating a multifunctional inertia-gravity separator with multiple novel boiler bodies, with the following revolutionary advantages: in the aspects of greatly reducing resource consumption and original emission concentration of boiler fume, eliminating the wear of a convection heating face and comprehensively improving boiler performance of the present invention, the structure style and separation mode of the present circulating fluidized-bed boiler cyclone separator in China and abroad have a large gap in comparison to the present invention and are infeasible.
The revolutionary advantages formed by 18 details of the multifunctional inertia-gravity separator provided by the present invention are as follows:
1. Ultra-low resistance saves the power consumption of the draft fan. This is because the fume flow velocity of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator is lower than the flow velocity of the cyclone separator.
2. Ultra-low energy consumption saves raw material. This may be indicated by saving by 90% of the wear-resistant material, by 50-80% of thermal insulating material, and by 100% of the metal material of a non-heating surface heat-resistant steel ventilator, a heat-resistant steel mesh and a steel cylinder of a dry high-temperature cyclone separator: and saving by 30-60% of steel and wear-resistant material and by 50-70% of thermal insulating material of a steam-cooling circular cyclone separator.
3. Ultra-low dust emission saves the investment in dust removing equipment and cost in maintenance and replacement. This is because, the highest value of the original emission concentration of the boiler fume by two-stage separation may be <1800 mg/m3.
4. Ultra-high separation efficiency eliminates the wear to the convection heating face and prolongs the service life of the whole boiler. This is because, the solid is directly conveyed to the storage bin by airflow under the action of a guiding fume directly-raising storage bin water-cooling wall, high concentration of gas and solid from the outlet of the hearth comes down with a sharp turn of 180° and then flows in a same direction to directly to the large capacity-expansion space to the storage bin; and, the sharply turned centrifugal force and drag force, blowing force of the airflow, the gravity of the solid and the ground gravitation may allow the velocity of the solid falling from up to down to be higher that the velocity of the airflow, so that the large capacity expansion of the high velocity outlet of the downward flue and the low velocity inlet of the upward flue create a condition that the separable specific gravity is higher the fine particles and ash in air.
5. Ultra-high combustion efficiency reduces the carbon content of the combustible. This may be indicated by the efficiency of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator and multi-stage separation, particularly the downward and upward flues, the turning passage and the large capacity-capacity-expanding space increasing the burn-out time of the combustible at the height of nearly the hearth in the boiler.
6. The advantage that the ultra-high separation efficiency of the primary water-cooling high-temperature separation may allow the shaft flue and convection heating face of a low-pressure steam and large-scale heating boiler to employ a shell shaft thread flue convection heating face and allow for shaft flue sealing and convective heat transfer strength is irreplaceable.
7. Two shortcomings of high-temperature coking due to low an ash fusion point and high-temperature corrosion of the heater during biomass and urban garbage power generation may be solved. This may be indicated by the radiative heat transfer and burn-out of the downward and upward flues and the large capacity expansion space of the full-water-cooling separator and the arrangement of the over-heater not in the separator.
8. The reduction of the carbon content of ash improves comprehensive energy efficiency. This may be indicated by the ultra-high consumption efficiency and the Ultra-low original fume emission.
9. Saving the maintenance cost of the separator improves comprehensive energy efficiency. This may be indicated by the water-cooling separator.
10. The reduction of heat low improves comprehensive energy efficiency. This may be indicated by the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator.
11. The boiler is started and stopped quickly and the separator is not coked. This may be indicated by the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator.
12. Single-stage and double-stage separation may replace the shortcoming of the wear and cost of maintenance and replacement of a buried pipe. This may be indicated by the scientific matching and adjusting of the dense phase zone temperature replaced buried pipe of the first-stage primary high-temperature inertia-gravity water-cooling separator and the secondary low-temperature water-cooling inertia-gravity separator.
13. The double-stage separation may replace the shortcoming of high high-pressure wind power consumption and difficult maintenance of an external heat exchanger: the secondary low-temperature inertia-gravity water-cooling separator may adjust the temperature of the dense phase zone, the heating surface of the primary high-temperature inertia-gravity water-cooling separator and the arrangement of the over-heater in the upward flue space of the primary high-temperature inertia-gravity water-cooling separator may be far larger than the heat transfer area of the external heat exchanger.
14. The bottleneck of uneconomical operation of the boiler <35 t may be solved. This may be indicated by the scientific design of dense and dilute phase zones, two structures partitioned by a equalizing, separating and heat storing device and the back-feeding valve directly being communicated to the hearth, the downward and upward flues and the large capacity expansion space and the like.
15. The size of the boiler may be reduced and the steel may be saved. This may be indicated by reducing the height of the boiler body, reducing the thickness of the refractory and thermal insulating material and the weight of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator.
16. Multiple functions of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator realize efficient utilization of the resource space, This may be indicated by efficient gas-solid separation, sufficient burning and heat exchange of the capacity expansion space, efficient heat transfer of the heater of the upward flue, the disturbance to the material in the storage bin by airflow cleaning wall fume in the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator.
17. The full coverage of hot-water, steam industrial boilers and heat-power cogeneration, station boilers from minimum to maximum may be realized; and, the selections of manufacturing enterprises of different coal types, different water qualities, different models of boilers, different areas, different custom demands, different customer bearing capacities and different construction installation equipment conditions may be adapted.
18. The advantage of competitive large-scale and ultra-large-scale coal powder station boilers may be realized. This may be indicated by the integral structure of the boiler, ultra-low resistance, ultra-low energy consumption, ultra-low fume emission, ultra-high separation efficiency and combustion efficiency, wide boiler coal adaptability and burning low-grade coal, high desulfurization and denitrification efficiency, low cost, and low raw coal smashing cost.
The meaning of the low resource consumption of the present invention is not inferior to any energy resource development. The basis of the low resource consumption of the present invention is as follows: large and medium-scale fluidized-bed boilers in the Chinese market at present are a plurality of dry high-temperature cyclone separators. The larger the boiler is, the greater the number of separators is and the larger the diameter is. Each separator cylinder is a wear-resistant and heat insulating layer having a thickness of 350 mm constructed in a heat-resistant steel mesh in a steel cylinder. The fume outlet of each separator is required to have a heat-resistance steel ventilator, where the wind velocity of the inlet of the ventilator is 20 m and the wind velocity of the outlet is 30 m. As a high flow velocity is likely to carry with solid particles of a certain grain size, the inlet of the convection heating face needs to be performed with wear-resistant processing. If any carelessness, it is difficult to avoid the wear of the heating surface.
In the present invention, regardless of the size of the boiler, the cylinder section of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator is of a rectangular structure. Two largest wall surfaces among four wall surfaces of the rectangular structure of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator completely are a rear wall of the hearth and a front wall of the shaft. As the transverse width of the boiler is about 2 times of the longitudinal depth, the two wall surfaces are heated on double surfaces without thermal insulating material, so that it is only required to perform heat insulation to two side walls of the rectangular separator in the present invention. Because the presence of the water-cooling wall may reduce the heat insulating thickness, the length of a single wide wall of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator is approximately equal to the diameter of one cyclone separator plus a distance between inlet and outlet tube sections. The perimeter of one cyclone separator is equal to or larger than the length of the two side walls of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separators. When the fume velocity of the downward flue of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator is 5 to 20 M, it is only required to provide wear resistance at one third of the rectangular structure, where the thickness of the wear resistance is 30 mm to 50 mm, For a boiler having four dry cyclone separators, the rectangular structure of the primary high-temperature water-cooling inertia-gravity separator, the secondary low-temperature inertia-gravity water-cooling separator or the single-stage high-temperature water-cooling inertia-gravity separator provided by the present invention only requires thermal insulating material of half a cyclone separator and wear-resistant material of one third of one cyclone separator. When the velocity of the downward flue is designed as ≤5 m, wear resistance or local wear resistance may be not employed.
The revolutionary advantages of multiple models of boilers of the present invention are as follows:
1. The single horizontal drum, full-membrane-wall hearth, full-water-cooling separator, full-membrane-wall shaft, full-water-cooling ceiling and good tightness and heat transfer performance of the boiler may simplify the thermal expansion design and installation process, reduce maintenance cost and prolong the service life of the boiler.
2. Due to single or double vertical and horizontal drums, the structure of the boiler body is in various forms, and more than one hundred series and hundreds and even thousands of types may be developed to adapt to the selections of enterprises of different coal types, different water qualities, different models of boilers, different areas, different custom demands, different customer bearing capacities and different construction installation equipment conditions; and, the full coverage of hot-water, steam industrial boilers and heat-power cogeneration, power plant boilers from minimum to maximum may be realized.
3. For the forced-circulating hot-water boiler having double horizontal drums, the full-water-cooling hearth, the full-water-cooling separator, the full-water-cooling ceiling, and fume to return up and down for 8 times, so that the fume route is long, the heat transfer effect is good, the multi-stage separation of gas, solid and ash greatly reduces the ash on the convector heating surface.
4. Shell shaft: the shaft is sealed and has no air leakage, so the fume emission loss is reduced; and, the shaft never needs to be maintained, so the maintenance cost is greatly saved, and the steel frame and refractory material of the shaft are saved.
5. The shell thread fume tube convection heating face is vertically designed and installed, so the convection heating face has efficient heat transfer, no ash deposition and stable heat efficiency.
6. The single vertical drum, the full-water-cooling ceiling and the drum are supported by water-cooling wall tubes on the front and rear sides, the process is advanced, and the steel frame is omitted.
7. Upper portions of all the single vertical drum, the vertical upper central header, and the equalizing, separating and heat storing device disposed on the upper part of the hearth are integrated together, and lower portions thereof are also integrated together, so ≤35 ton of steam boiler may realize separate manufacture fields and separate assembling in a factory, so that the quality and efficiency of manufacturing and installation may be greatly improved, combustion is enhanced, internal and external gas-solid separation performance is improved, and various shortcomings caused by the reduction of the height of the boiler body are solved.
8. The phase-transformation heat-exchange hot-water boiler for the fluidized-bed having vertical drums may be kept from scaling, oxygen corrosion, pollution discharge, softened water equipment and deoxygenization equipment, and is an irreplaceable product having the advantages of high efficiency, energy conversation, waver conversation, consumption reduction and emission reduction in the hot-water and heat supply field.
9. For the phase-transformation heat-exchange hot-water boiler for the fluidized-bed having vertical drums, the boiler body forms a framework itself and supports by itself, the structure is compact, the integrality is high, and the steel frame is greatly omitted; the drum header bundles are vertically and horizontally communicated to each other, so the boiler water is circulated and uniformly descended and ascended for automatic adjustment, so that the natural circulation is safer and more reliable; the perfect matching of the heat exchanger and the boiler makes the advantages of the large-scale phase-transformation hot-water boiler more prominent.
10. For the vertical drum fluidized-bed phase-transformation hot-water boiler, the full-water-cooling wall structure and process are advanced, and fume is separated initially through multiple loops in the boiler, so that original emission concentration of fume is greatly reduced; the ash on the heating area is greatly reduced, and both thermal resistance and flowing resistance are reduced: fume are circulated for five cycles in the boiler, and the convection bundles are vertically arranged for transverse washing, so that the fume flow path is long, the heat exchange effect is excellent and the thermal efficiency is high.